Demonstration of the importance of biphasic oleic acid delivery for enhancing the bioavailability of propranolol in healthy volunteers

Two studies involving six healthy volunteers were carried out to assess the importance of biphasic rapid and sustained release of oleic acid in enhancing the bioavailability of propranolol using the HALO® drug delivery system. The results of the first study showed that mean Cmax and AUC values for propranolol were increased by at least 300% using biphasic HALO®-propranolol capsules compared with Half Inderal® LA, both containing an 80 mg dose of propranolol. In the second study no significant differences in propranolol bioavailability were observed between monophasic enteric-coated capsules containing only the sustained release component of the HALO® delivery system and Half Inderal® LA, when an equivalent 80 mg dose of propranolol was administered. The use of improved enteric-coating procedures increased propranolol bioavailability compared with previous studies using biphasic HALO®-propranolol capsules. The possible explanations for the effectiveness of biphasic rapid and sustained delivery of oleic acid for enhancing the bioavailability of propranolol are discussed.